Make az container show return exact image used by containers

**Is your feature request related to a problem? Please describe.**
This feature request is about Azure Container Instances. I want to know exactly which image my container groups are currently running. As of now, it does not seem possible to get this information with az cli. I can only retrieve the container image names.

**Describe the solution you'd like**
I want `az container show --name "mycontainername"`, for each container in the container group, to return an object which contains a field `imageHash`, which has a value equal to the SHA256 hash of the final layer of whichever image the container instance is currently running.

**Describe alternatives you've considered**
None

**Additional context**
I'm using an Azure Container Registry to pull my images from.